Comparison of bovine serum albumin glycation by ribose and fructose in vitro and in vivo

Advanced glycation end products (AGEs) play a critical pathogenic role in the development of diabetic complications. Recent studies have shown that diabetes is associated with not only abnormal glucose metabolism but also abnormal ribose and fructose metabolism, although glucose is present at the highest concentration in humans. The glycation ability and contribution of ribose and fructose to diabetic complications remain unclear. Here, the glycation ability of ribose, fructose and glucose under a mimic physiological condition, in which the concentration of ribose or fructose was one-fiftieth that of glucose, was compared. Bovine serum albumin (BSA) was used as the working protein in our experiments. Ribose generated more AGEs and was markedly more cytotoxic to SH-SY5Y cells than fructose. The first-order rate constant of ribose glycation was found to be significantly greater than that of fructose glycation. LC-MS/MS analysis revealed 41 ribose-glycated Lys residues and 12 fructose-glycated residues. Except for the shared Lys residues, ribose reacted selectively with 17 Lys, while no selective Lys was found in fructose-glycated BSA. Protein conformational changes suggested that ribose glycation may induce BSA into amyloid-like monomers compared with fructose glycation. The levels of serum ribose were correlated positively with glycated serum protein (GSP) and diabetic duration in type 2 diabetes mellitus (T2DM), respectively. These results indicate that ribose has a greater glycation ability than fructose, while ribose largely contributes to the production of AGEs and provides a new insight to understand in the occurrence and development of diabetes complications.     

In vitro effect of rabbit anti sea star lymphocyte serum on axial organ cells

The axial organ (AO-cells) of the sea star Asterias rubens is a primitive immune organ. The total population was fractionated or not into two populations: adherent (B-like) and non adherent (T-like) to nylon wool. Rabbit anti sea star lymphocyte serum induces the proliferation of axial organ cells. The T-like antiserum stimulates the T-like cells exclusively; the whole axial organ cell antiserum only stimulates the whole axial organ cell population.     

Cell number and incidence of chromosomal anomalies in bovine blastocysts fertilized in vitro followed by culture in vitro or in vivo in rabbit oviducts

The total number of cells and the incidence of chromosomal anomalies in bovine blastocysts cultured in vitro or in vivo in rabbit oviducts were investigated from the four-cell stage after in-vitro fertilization of in-vitro matured follicular oocytes. The total number of cells (80 vs 179) in the oviduct-cultured blastocysts was nearly double that (43 vs 80) of blastocysts cultured in vitro at early and expanded blastocyst stages. In both culture systems, the total number of cells increased with the stage of development. Mitotic index (number of metaphase plates/total number of cells) of blastocysts decreased with development from early (11.5 vs 13.8%) to hatched blastocyst stages (4.8 vs 2.8%) in in-vitro and in-vivo culture systems, respectively. Overall, chromosomal anomalies were observed in 37.5% (27 27 ) of embryos cultured in vitro and in 28.0% (7 24 ) cultured in vivo, respectively. Incidence of chromosomal anomalies did not depend on such factors as culture system or stage of development. Most chromosomal anomalies were polyploid and mixoploid cells.     

Studies on binding interactions between clenbuterol hydrochloride and two serum albumins by multispectroscopic approaches in vitro

In this study, binding properties of clenbuterol hydrochloride (CL) with human serum albumin (HSA) and bovine serum albumin (BSA) were examined using constant protein concentrations and various CL contents under physiological conditions. The binding parameters were confirmed using fluorescence quenching spectroscopy at various temperatures. The experimental results confirmed that the quenching mechanisms of CL and HSA/BSA were both static quenching processes. The thermodynamic parameters, namely, enthalpy change (ΔH) and entropy change (ΔS), were calculated according to the van't Hoff equation, which suggested that the electrostatic interactions were the predominant intermolecular forces in stabilizing the CL–HSA complex, and hydrogen bonds and van der Waals force were the predominant intermolecular forces in stabilizing the CL–BSA complex. Furthermore, the conformational changes of HSA/BSA in the presence of CL were determined using the data obtained from three‐dimensional fluorescence spectroscopy, ultraviolet‐visible absorption spectroscopy and circular dichroism spectroscopy. Copyright © 2013 John Wiley & Sons, Ltd.     

Characterization of antigenic proteins from Tritrichomonas foetus recognized by antibodies in rabbit serum, bovine serum and bovine cervicovaginal mucus

Tritrichomonas foetus is an obligate parasite of the bovine urogenital tract and is recognized as 1 of the more common infectious agents causing decreased reproductive efficiency in beef cattle. Infections result in reproductive failure and produce considerable economic loss. Vaccination of heifers with vaccines containing T. foetus induces elevated serological responses to many T. foetus antigens, decreases the rate and/or length of infection with T. foetus, and decreases fetal loss caused by infection. Because T. foetus infections are usually limited to lumen and mucosal surfaces of the reproductive tract, it has been assumed that protection from infection and abortion is partially mediated by immunoglobulins in the uterus and vagina. The objective of this study was to identify and characterize specific antigens of T. foetus that show promise for use in a recombinant vaccine that will generate a protective mucosal immune response in cattle. Surface proteins were identified by using polyclonal rabbit anti-trichomonal sera eluted from paraformaldehyde-fixed cells. Analyses of these proteins, utilizing mucosal antibodies from vaccinated and convalescent cows, have identified proteins involved in generating a local immune response. Western immunoblot analysis indicates that these proteins are well conserved and are excellent candidates for incorporation into a recombinant vaccine.     

Some characteristics of rabbit anti sea star T-like cells serum

Preliminary experiments show that rabbit anti sea star T-like serum recognizes T-like cells from two different geographic regions but not mouse T lymphocytes and man T lymphocytes. On the other hand, cytotoxicity reactions do not occur with this serum.     

Studies of rabbit serum transferrin

Rabbit serum transferrin is isolated by a procedure designed to preserve its conformation and disulfide linkages. A progress report is presented on the determination of its amino acid sequence, as part of studies on its primary, secondary and tertiary structure. The sequence of 378 residues, of the approximately 680 residues in the molecule, are determined. Observations are made on the site of carbohydrate attachment, iron binding sites and half-cystine residue location. The results are discussed in relation to the X-ray crystallographic studies of human lactoferrin (lactotransferrin) and of rabbit serum transferrin being made in other laboratories.     

Changes in bovine mammary insulin binding during pregnancy and lactation

1. Binding of insulin to microsomes from mammary glands of pregnant and lactating dairy cows was characterized. 2. Binding affinities of the insulin receptor did not change from pregnancy to lactation. 3. Maximal specific binding occurred in microsomes from cows in mid-pregnancy and declined in microsomes from cows in late pregnancy. 4. Insulin binding continued to decrease from early to mid-lactation and increased during late lactation. 5. Results indicate that decreased sensitivity in mammary tissue from lactating dairy cows is at least in part a result of a reduction in insulin receptor number. 6. Results demonstrate further physiological differences between the ruminant and non-ruminant mammary gland.